Mapping the seabed of the Belgian part of the North Sea to assist in a science-based approach to management

Knowledge of the spatial distribution of sediments, the impact of human activities on the seabed and the natural evolution of the seabed is important to assist in a more sustainable management of the Belgian Part of the North Sea (BPNS). Sediments are an essential part of any aquatic system and are the key for a better understanding of the marine ecosystem; moreover, they are a valuable socio-economic resource for construction material and beach nourishment; therefore, they are extracted increasingly. Research on sediment nature and processes are important also for the optimisation of dredging and dumping activities, the implantation of windmill farms, seabed constructions, cables and pipelines, the designation of marine nature reserves and, generally, any spatial planning initiative.Related to the BPNS research, the Renard Centre of Marine Geology (RCMG) of Ghent University has been/is actively involved in various inter- and multidisciplinary projects. Throughout these projects, a research strategy is followed that balances between process/modelling studies, and the optimization of the use of various acoustical and sampling techniques.Results from three research projects, related to the mapping of the seabed of the BPNS, will be presented. During the Marebasse project (Belspo, SPSDII; http://users.ugent.be/~vvlancke/ Marebasse/), significant new sampling and acoustical data was acquired in typically mud-, sand- and gravel-dominated areas (Van Lancker et al., 2007). On the scale of the BPNS, new thematic maps, related to the bathymetry, sedimentology and morphology, were produced. Automated modelling of these physical data layers, based on advanced geostatistical methods, have resulted in physical habitat maps with ecological relevance. On a smaller scale, impact studies of aggregate extraction and dumping of dredged material were performed on selected sites, integrating results from geo-acoustical surveys and terrain verifications. Results have shown that, on a short- to medium-term, the effects seem relatively localised. All results are integrated into a Geographical Information System GIS@SEA (The physical seabed GIS to support Studies and Environmental Applications).As the Marebasse project focussed on the spatial variability of the seabed nature and the short- to medium-term impact of human activities, knowledge of the natural evolution of the seabed, its response to sea-level rise and the long-term anthropogenic impact remains poor. These issues are investigated now in the QUEST4D project (Belspo, SSD; http://www.vliz.be/projects/Quest4D/). Through quantification of erosion/sedimentation patterns, the natural evolution will be compared against the impact of human activities. Results will be presented of the area north of the Vlakte van de Raan, including the dumping ground Br&W S1. Acoustical maps of the seabed reveal different sedimentation and erosion patterns, originating from natural processes and human-induced activities (Van Lancker et al., 2008). The socio-economic importance of seabed resources is further dealt with in theRESOURCE-3D project (Belspo Targeted Action), in which a 3D reconstruction of the internal structure of sandbanks is aimed at. A case study on the Kwinte Bank will be presented

Acoustic habitat modelling for the mapping of biological communities

In the framework of the MAREBASSE project (‘‘Management, Research and Budgeting of Aggregates in Shelf Seas related to End-users’’, EV/02/18, Van Lancker et al. 2005) and the MESH project (“Mapping European Seabed Habitats, Interreg IIIb; www.searchmesh.net), biologically relevant habitat maps are produced, based on multibeam acoustic datasets, ground truthed with physical and biological samples. The habitat map production comprised of the following four key steps: (1) getting the best out of the ground truth data; (2) selecting and deriving the best available input and most appropriate data coverages; (3) using the most appropriate techniques for interpreting the data through integration and modelling, and; (4) designing the map layout to create a map fit for purpose. Results are presented where classes derived from acoustic seabed classification are translated into habitat maps. Cross tabulation is used to correlate biological ground truthing data with the acoustic classes. Finally, habitat maps are produced, representing the likely occurrences of the different macrobenthic communities occurring on the Belgian part of the North Sea (BPNS). For the study areas of Oostende, Hinder Banken, Sierra Ventana, habitat maps of macrobenthic communities have been created. The habitat maps are based on a cross tabulation of acoustic backscatter classification of the multibeam images, overlaid with biological samples worked out on a macrobenthic community level

Geostatistical modelling of sedimentological parameters using multi-scale terrain variables: application along the Belgian part of the North Sea

In the nowadays highly pressurized marine environment, a science-based approach to management becomes increasingly important. In many cases, the sediment nature and processes are the key to the understanding of the marine ecosystem, and can explain particularly the presence of soft-substrata habitats. For predictions of the occurrence of species and habitats, detailed sedimentological information is required. This paper presents a methodology to create high quality sedimentological data grids of grain-size fractions and the percentage of silt-clay. Based on a multibeam bathymetry terrain model, multiple sources of secondary information (multi-scale terrain variables) were derived. Through the use of the geostatistical technique, Kriging with an external drift (KED), this secondary information was used to assist in the interpolation of the sedimentological data. For comparison purposes, the more commonly used Ordinary Kriging technique was also applied. Validation indices indicated that KED gave better results for all of the maps

Growth in densely populated Asia: implications for primary product exporters

Economic growth and integration in Asia is rapidly increasing the global economic importance of the region. To the extent that this growth continues and is strongest in natural resource-poor Asian economies, it will add to global demand for imports of primary products, to the benefit of (especially nearby) resource-abundant countries. How will global production, consumption and trade patterns change by 2030 in the course of such economic developments and structural changes? We address this question using the GTAP model and Version 8.1 of the 2007 GTAP database, together with supplementary data from a range of sources, to support projections of the global economy from 2007 to 2030 under various scenarios. Factor endowments and real gross domestic product are assumed to grow at exogenous rates, and trade-related policies are kept unchanged to generate a core baseline, which is compared with an alternative slower growth scenario. We also consider the impact of several policy changes aimed at increasing China's agricultural self-sufficiency relative to the 2030 baseline. Policy implications for countries of the Asia-Pacific region are drawn out in the final section

Hypercomplex Integrable Systems

In this paper we study hypercomplex manifolds in four dimensions. Rather than using an approach based on differential forms, we develop a dual approach using vector fields. The condition on these vector fields may then be interpreted as Lax equations, exhibiting the integrability properties of such manifolds. A number of different field equations for such hypercomplex manifolds are derived, one of which is in Cauchy-Kovaleskaya form which enables a formal general solution to be given. Various other properties of the field equations and their solutions are studied, such as their symmetry properties and the associated hierarchy of conservation laws.Comment: Latex file, 19 page

ED012. Potencial efecto del cambio climático en la biodiversidad de invertebrados del suelo en Yasuní

Climate change is a current global problem induced anthropically, which predicts drier and warmer future conditions with strong drought events and high temperatures for much of the Amazon region. Additionally, negative repercussions on ecosystem function mediated by the edaphic fauna (i.e decomposition of organic matter) are expected. Based on these projections, the focus of this study is on the impact of warming and drought on the structure of soil invertebrate communities in an Amazonian tropical forest through their response in terms of abundance, diversity, and functional groups to drought exposure and/or increased temperature. The experimental design was carried out in the Yasuní National Park, in an area of 15 × 20 m with 40 × 45 cm quadrants to expose them to a 3 °C increase in surface soil temperature and drought induction by installing small roofs that isolate water. Preliminary results are shown with the processing of 20 % of samples. The morphospecies under study were grouped into clusters according to their function. Additionally, the effect of the treatments was overlapped according to the NMDS (Non-Metric Multidimensional Scaling) analysis, suggesting that there is little difference between them. Moreover, the most abundant groups were those of ants and mites. In this way, it will be possible to show if this trend is maintained or changed when processing 100 % of the samples. This research demonstrates that understanding soil biodiversity can help us reconnect ecosystem services with soil biodiversity, in search of maintaining a balance in their functions.El cambio climático es una problemática actual global inducida antrópicamente, que predice condiciones futuras más secas y cálidas con fuertes eventos de sequía y altas temperaturas para gran parte de la región amazónica. Adicionalmente, se esperan repercusiones negativas en la funcionalidad del ecosistema mediada por la fauna edáfica (ej. descomposición de la materia orgánica). En base a estas proyecciones, el enfoque de este estudio se centra en el impacto del calentamiento y sequía en la estructura de comunidades de invertebrados del suelo en un bosque tropical amazónico mediante su respuesta en términos de abundancia, diversidad y grupos funcionales ante la exposición a sequía y/o al aumento de temperatura. El diseño experimental se llevó a cabo en el Parque Nacional Yasuní, en un área de 15 × 20 m con cuadrantes de 40 × 45 cm para exponerlos a un aumento de 3 °C en la temperatura del suelo superficial y la inducción a la sequía instalando pequeños techos que aíslen el agua. Se muestran resultados preliminares con el procesamiento del 20 % de muestras. Las morfoespecies en estudio se agruparon en conglomerados acorde a su función. Adicionalmente, el efecto de los tratamientos se vio solapado según el análisis del NMDS (escalamiento multidimensional no métrico), lo que sugiere que existe poca diferencia entre ellos. Además, los grupos más abundantes fueron los de las hormigas y ácaros. De esta manera, se podrá evidenciar si esta tendencia se mantiene o cambia al procesar el 100 % de las muestras. Mediante esta investigación se demuestra que comprender la biodiversidad del suelo puede ayudarnos a reconectar los servicios de los ecosistemas con la biodiversidad edáfica, en búsqueda de mantener el equilibrio en sus funciones

Recognizing the seafloor’s characteristics using habitat signatures

Seafloor images become increasingly available, both derived from video or photographs and from acoustic remote sensing. Very-high resolution acoustic imagery has indeed the potential of depicting a recognisable sign on an image that relates to a physical and biological nature, i.e. its habitat signature. Still, most of this information is stored at institutes or universities and no up-to-date comprehensive compilation is yet available. Moreover, the acoustic imagery often remains hard to interpret; this is mainly because of the multitude of factors influencing the image and the lack of reference material. When an interpreter studies a remote sensing image, he indeed needs to refer to particular textures and patterns that are recognisable on the image and relate that to reality. Ground truthing remains crucial; still comparison with a large number of similar cases is a necessity. In the framework of marine environmental issues this becomes increasingly important and the need for sound interpretations is real. To anticipate on this need, a web-based catalogue of seabed habitat signatures is being built in the framework of the MESH project (Mapping European Seabed Habitats), for both scientists and non-scientists. The catalogue contains a collection of images produced by different remote sensing techniques (acoustic and optically derived images, photographs and video). As such, the results of the different techniques can be compared and can strengthen interpretations in view of seabed assessments. The catalogue has a comprehensive list of metadata per habitat signature, both in terms of its physical and biological environment and the conditions under which the signatures were generated. The web catalogue is easy manageable. Habitats can be searched using their own name or by typing a key word or choosing a EUNIS code or making a query on physical factors. For every habitat one or more significant locations in the Mesh area are chosen and every location displays all the signatures available. Every location is identified by its coordinates (lat., long.) to be easily positioned on the MESH webGIS (http://www.searchmesh.net/webGIS). The signatures are presented as little thumbnails to let the web user have an easy overview. These link to a page where a description of the image, an enlarged image and all technical data referred to it can be found. The catalogue will largely increase the visibility of how the seafloor looks like, but above all it is hoped that it will assist in the interpretation of newly acquired data in view of - 48 - environmental assessments. Any potential contributor to this catalogue is invited to share their images to a wider European community. The web-catalogue is developed at Ifremer (http://www.ifremer.fr/meshmalo/ essai_signatures). RCMG is responsible for the input of imagery related to the Belgian part of the North Sea

Mud Origin, Characterisation and Human Activities (MOCHA): Final report

The cohesive sediments, which are frequently found in the Belgian nearshore zone (southern North Sea), are of different age such as tertiary clays and Holocene, modern and recently deposited muds. The area is characterised by a turbidity maximum. The source areas of the recently deposited muds and the effect of human impact vs. natural processes on the distribution and/or erosion of these sediments have been investigated using historic and recent bottom samples, in situ and remote sensing (satellite images) SPM concentration measurements, numerical modelling, GIS and clay mineral and microfossil analysis. The Schelde estuary, the potential erosion areas of cohesive sediments on the BCS and adjacent areas and the SPM transport through the Dover Strait have been considered as possible source areas.The historic bottom samples have been collected in the beginning of the 20th century, the quality of these samples and the meta-information is very high and they have proven to be a major reference to understand the evolution of the cohesive sediment distribution. The recent bottom samples consist of box core, Reineck core and Van Veen grab samples collected during the last 10 years. The processing of the historic and recent data on cohesive sediments was mainly based on field descriptions of the samples (consolidation, thickness) and morphological evolution. On some of the recent samples radioactive and gamma densitometric measurements have been carried out. During the processing the emphasis was put on the occurrence of thick layers (>30 cm) of freshly deposited to very soft consolidated mud and of clay and mud pebbles, because these sediments are witnesses of changes.Satellite images, in situ measurements and a 2D hydrodynamic numerical model have been combined to calculate the long term SPM transport through the Dover Strait and in the southern North Sea. The satellite images (SeaWiFS) provide synoptic views of SPM concentration. The representativness of SPM concentration maps derived from satellites for calculating long term transports has been investigated by comparing the SPM concentration variability from the in situ measurements with those of the satellite data. It is underlined that SPM concentration measurements should be carried out during at least one tidal cycle in high turbidity areas to obtain representative values of SPM concentration.Areas where the thickness of the Quaternary cover is less than 2.5 m were defined as potential erosion areas of Palaeogene clay containing deposits. In the framework of this project, the geological data related to the BCS have been reviewed and the relevant information was compiled into a GIS. This also included a small part of the French continental shelf. Additionally information was added from vibrocores analysis and Dutch geological data. Approximately 20 % of the BCS, 6 % of the small part of the French area and only 3% of the Dutch study area could possibly serve as a source for fine suspended sediments. Quaternary muds are mostly presented in the 2 eastern nearshore area; on the Dutch part they occur more offshore. Their occurrence represents 11% of the BCS and approximately 35% of the Rabsbank area Cretaceous microfossils are present in all samples and have been transported into the area with the residual water transport. Material from the east, in particular from the Eocene-Oligocene transitional strata, has been found in the eastern nearshore area up to about Oostende. This zone coincides with the extension of the Holocene mud and could indicate an erosion of these sediments and/or a transport of clay minerals from the Schelde estuary.Clay mineral analysis has been carried by two approaches in order to determine source areas. The results of the second approach show that no systematic differences in the clay mineralogy depending on geographic location could have been found within the samples. The results clearly prove the necessity of using more elaborate sample preparation procedures in examining the provenance of the mud deposits.Thick layers of fresh mud were deposited in the beginning of the 20th century mainly in a narrow band along the coast from about Nieuwpoort up to the mouth of the Westerschelde. These deposits were mainly the result of natural morphological changes. Today, most of the depositions of thick layers of fresh mud have been induced by anthropogenic operations, such as dumping, deepening of the navigation channels and construction and extension of the port of Zeebrugge. Comparing the actual situation with the situation 100 years ago reveals that the area around Zeebrugge where fresh mud is deposited extends more offshore today